When you have to check for the presence of a value in a list and set a flag based on it, we can avoid typical:
set default => check => update
routine in Python and condense it to a single line like this.
orders = ['pizza', 'coke', 'fries']
order_book = {}
# Setting an yes or no flag in another dictionary or object
order_book['pizza'] = False
if 'pizza' in orders:
order_book['pizza'] = True
# Simpler Version
order_book['pizza'] = 'pizza' in orders